Water Solutions:
The manganese greensand/Anthracite iron filter is the most common bacterial iron removal system that HSW uses and the most effective.
The manganese greensand/Anthracite iron filter is the most common bacterial iron removal system that HSW uses and the most effective. It can be used successfully for iron concentrations up to approximately 6 mg/L. Iron is oxidized by a coating on the manganese greensand. The media is continually regenerated with the chlorine residual in the water to replenish the oxygen on the greensand. Continued successful operation requires an availability at least 20 L per minute flow for proper backwash, pH above seven, and regular regeneration. Failure to regenerate often enough can ruin the filter media. Please note: A chlorination system is also required to provide the regenerate. Even though a chlorination system is required in this design, in the long run its cheaper and safer than using specialized oxidizing products like potassium permanganate. Pot perm will regenerate the iron filter media but the cost of the product is very high and the use of pot perm is tricky. Chlorine is much more stable and also provides benefits than just an oxidizer for the iron filter.
For non-bacterial iron a great option is a backwash Birm filter. The media does not require a regenerate. This system can handle iron levels up 10 mg/L of ferrous or ferric iron. The media will have to be replaced occasionally. The time frame will depend on water usage and iron levels.
A water softener will generally remove up to 2.0 mg/L of iron. The iron must be in the ferrous (clear water) state, or the iron will damage the softener resin. Bacterial iron cannot be removed by a water softener.
Care must be taken if a softener is used to remove iron because iron tends to clog and foul the softener resin. A resin cleaning compound must be used regularly to protect the resin. The most common resin cleaning compounds contain sodium hydrosulfite or phosphoric acid. Some water softener salt contains a resin cleaner. An upsized softener would be recommended. The extra amount of softening resin will help with the removal of the iron. Installation of a pre-filter is recommended to reduce iron levels as well as prevent excessive particulates from entering water softener.
Click here for more info on water softeners >
Another system for iron removal is chlorination. Chlorination, followed by a retention tank and filtration, can remove moderate concentrations of iron, iron bacteria, and high levels of hydrogen sulfide. The iron is oxidized by the chlorine. A sediment filter is used to remove the rust particles and an activated carbon filter can be installed to remove excess chlorine. The pH of the water must be above seven. The filter will have to be replaced as often as once a month. If iron levels are in the range of 1-2PPM, then this is an economical option, but one needs to keep in mind the cost of filters.
